Project Summary All organisms share the common requirement of acquiring resources from the environment to build and maintain anatomical structures and to fuel biological functions. How organisms allocate their limited resources towards reproduction, somatic maintenance, and storage, underlies a vast array of phenotypes critical to human health. Viewed within an energy allocation context, obesity and metabolic syndrome result from a maladaptive over-allocation of resources to storage, aging is a necessary consequence of decreased allocation to somatic maintenance, and ?athletic? amenorrhea involves an allocational shift away from reproduction. This proposal describes an experimental evolution approach using the well-characterized model system, Drosophila melanogaster, to understand the genetic basis and evolution of the coordination between allocation and resource availability. A fully genetically characterized population will be exposed to three environments, each of which is predicted to select for a different resource allocation pattern. The proposed experiments will determine the genomic, physiological, and high-level phenotypic changes that occur during the evolution of a trait of fundamental importance to many of the most critical health concerns for modern human populations (e.g., obesity, metabolic syndrome, and age-related diseases). The major objectives of the research include 1) directly observing how resource allocation patterns towards reproduction, maintenance (survival), and storage evolve during the course of adaptation different resource availability regimes, 2) tracking genomic level changes to identify genes affecting the coordination of resource availability with resource allocation, 3) characterizing intermediate phenotypic changes across the genotype to phenotype map, and 4) documenting the degree of parallel evolution at different levels of the genotype to phenotype map.